Treating nausea and vomiting in palliative care: a review

Nausea and vomiting are portrayed in the specialist palliative care literature as common and distressing symptoms affecting the majority of patients with advanced cancer and other life-limiting illnesses. However, recent surveys indicate that these symptoms may be less common and bothersome than has previously been reported. The standard palliative care approach to the assessment and treatment of nausea and vomiting is based on determining the cause and then relating this back to the "emetic pathway" before prescribing drugs such as dopamine antagonists, antihistamines, and anticholinergic agents which block neurotransmitters at different sites along the pathway. However, the evidence base for the effectiveness of this approach is meager, and may be in part because relevance of the neuropharmacology of the emetic pathway to palliative care patients is limited. Many palliative care patients are over the age of 65 years, making these agents difficult to use. Greater awareness of drug interactions and QT(c) prolongation are emerging concerns for all age groups. The selective serotonin receptor antagonists are the safest antiemetics, but are not used first-line in many countries because there is very little scientific rationale or clinical evidence to support their use outside the licensed indications. Cannabinoids may have an increasing role. Advances in interventional gastroenterology are increasing the options for nonpharmacological management. Despite these emerging issues, the approach to nausea and vomiting developed within palliative medicine over the past 40 years remains relevant. It advocates careful clinical evaluation of the symptom and the person suffering it, and an understanding of the clinical pharmacology of medicines that are available for palliating them.